; The first half of the ROM will not be used, so PAD it
FILLVALUE $FF
ORG $0000
PAD $8000

LCD_INS EQU $6000
LCD_DAT EQU $6001
DELAY_CNT EQU $0010

Init:
	LDA #$38
	STA LCD_INS
	JSR WaitLcd
	JSR Delay

	LDA #$38
	STA LCD_INS
	JSR WaitLcd
	JSR Delay
	
	LDA #$38
	STA LCD_INS
	JSR WaitLcd
	JSR Delay
	
	LDA #$38
	STA LCD_INS
	JSR WaitLcd
	JSR Delay
	

	; On/Off control
	LDA #$0C
	STA LCD_INS
	JSR WaitLcd
	JSR Delay

	; Clear display
	LDA #$01
	STA LCD_INS
	JSR WaitLcd
	JSR Delay

	; Entry Mode Set
	LDA #$06
	STA LCD_INS
	JSR WaitLcd
	JSR Delay

	; Set DDRAM Address
	LDA #$80
	STA LCD_INS
	JSR WaitLcd
	JSR Delay

	; Move A character to LCD
	;LDA #$41
	;STA LCD_DAT
	;JSR WaitLcd
	;JSR Delay
	JSR WriteMessage

MainLoop:
	NOP
	NOP
	NOP
	NOP
	JMP MainLoop


; Wait until LCD is not busy
WaitLcd:
	LDA #$80
	BIT LCD_INS
	BNE WaitLcd
	RTS

Delay:
	LDA #$00
	STA DELAY_CNT
Delay_1:
	ADC #$01
	CMP #$00
	BNE Delay_1
	INC DELAY_CNT
	LDA #$10
	CMP DELAY_CNT
	BNE Delay_1
	RTS

WriteMessage:
	LDY #$00
WriteMessage_0:
	LDA (MSG),Y
	CMP #$00
	BEQ WriteMessage_End
	STA LCD_DAT
	JSR WaitLcd
	INY
	JMP WriteMessage_0
WriteMessage_End:
	RTS

MSG
	DB "+------------------+"
	DB "|  Nintendo DS     |"
	DB "| Better than a    |"
	DB "+------------------+"
	DB $00

; At the very end (almost), we need to declare where the PC should be initialized at.
; For our purposes, we'll start it at the beginning of the ROM area.
ORG $FFFC
DB $00, $80, $00, $00